Causes and Consequences of Water-Mediated Pattern Formation in Arid African Rangelands

2019 Faculty Research Award

Award Period: 2019-2021

Corina Tarnita and Robert Pringle, associate professors of ecology and evolutionary biology, will study how water, nutrients, soil type, and large-herbivore activity interact to shape plant communities and spatial patterns in semi-arid African rangelands. Using experimental infrastructure from their related 2016 Grand Challenges project, Tarnita and Pringle will manipulate water availability, nutrient availability and herbivory on different soil types to examine the mechanisms that govern tree-grass interactions and tree species diversity. Based on their experiments, they will incorporate the interactions among these multiple factors into existing theoretical models of vegetation self-organization. Their work aims to provide one of the first experimentally grounded tests for the theory they developed to explain how water limitation determines vegetation patterning. African rangelands provide crucial livestock-grazing and agricultural land to millions of people. Climate change is expected to increase dry periods while also producing more intense periods of rainfall and potential flooding. Yet, there is currently little data on how ecosystems will respond to intense shortages and sudden onslaughts of water. Tarnita and Pringle plan to incorporate their findings into theoretical frameworks that can serve as early-warning indicators of ecosystem collapse in drought-stressed ecosystems.

Educational Impact

Princeton undergraduates serving as PEI summer interns will be recruited to take part in data collection, with the aim of preparing them for independent senior-thesis research. As part of their 2016 project, Tarnita developed water-related lectures as part of a freshman seminar on the mathematical modeling of biological questions, including pattern formation, catastrophic transitions, early-warning indicators, game theory, and epidemiology. With the current grant, she will expand and incorporate those topics into her course “Mathematical Modeling in Biology and Medicine.” Tarnita and Pringle also plan to develop a joint freshman seminar that looks at the causes and consequences of pattern formation globally — particularly its potential use as an early-warning indicator for catastrophic system collapse — by combining theoretical and experimental perspectives.

Participating Departments


Associate Professor of Ecology and Evolutionary Biology
Associate Professor of Ecology and Evolutionary Biology